Citronella works by masking scents that are attractive to insects namely carbon dioxide and lactic acid in humans according to the NPIC.
One benefit of using citronella as mosquito repellent is that it is safe and non-toxic to humans and animals (and even the insects). Although some people can have mild allergic reactions to the oil, even ingesting citronella will not affect humans it is simply broken doen and passed out of the body through urine.
What is Citronella?
Citronella oil is a colorless or light yellow liquid with a characteristic woody, grassy or lemony ador. It is flammable and if the vapors are inhaled, this could cause an initial stimulation followed by depression of the central nervous system..
Citronella oil has minimal or no risk to wildlife and environment due to its toxic levels being low and its use being limited. Therefore, it can be used around the home with no expected adverse effects.
The fumes of citronella oil are said to be potentially toxic to birds; however, this is because it is often used in conjunction with other essential oils in air fresheners – therefore, the potential to cause toxicity.